What are the Results of Aging

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What are the Results of Aging (biology of
aging) Winter 08 Lecture 4 Chapter 4
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Pathological Aging Premature Aging
Progeria Developmental
Werners Syndrome
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• Vision
• Hearing
• Taste
• Smell
• Skin
• Hair
• Weight

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Skin
The membranous tissue forming the external -
covering largest organ New skin Young skin 3
to 4 wks Older Skin 4 to 5 wks

• Epidermis
• squamous, basal cells melanocytes
• Dermis
• collagen (support structure, 75)

• Loss of
• Collagen (thinner finer) elastin fibers
  (connective tissues more rigid, less flexible)
• fat tissue
• atrophy of sweat glands
• blood vessels fragile (angiomas)

Lack of turnover of new cells
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Hair

• Loss of melanin in follicles
• life cycle of 4 to 5 years
• strand become smaller
• Genetic ? whites earlier

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Height Weight
Men -1.25 in HT Women -2 in HT
Men Women Metabolism slows down 3 every 10
years so by 65 ?20 reduction
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So, does obesity contribute to risk of death in
older adults
Diehr et al. (2002) N 4,317 older adults
65-100 yrs Examined the relationship between BMI
and Mortality Longitudinal Study (wt/height X
704.5) No correlation between WT
Mortality in fact higher risk of death if lower
wt. BMI of 20 (55 120 lbs) or lower Higher
mortality rate than higher BMIs (Women) 10 or
more weight loss since 50 (both men
women) Higher death rate (15.9 30.3)
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The Senses

• Vision
• Hearing
• Taste
• Smell

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• Visual impairment most common sensory problem
• 95 wear glasses (across cultures)
• pupil 1/3 size (iris more rigid) (by 60 vs 20)
• 5 cannot read
• 20 cannot drive

• Vision

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Normal Vision
Problem in lens ? Cataracts protein clumping
together
Problem in the macula (fovea) Macular
Degeneration loss of acuity and center vision
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• Hearing

• 30 65 up significant hearing impairment
• 25- between 65 and 74
• 50- 75 up difficulty hearing
• 10dB reduction in hearing sensitivity each
  decade after 60
• older men more likely to have hearing loss than
  older women

• ear structures deteriorates
• eardrum often thickens
• inner ear bones and other structures are
  affected

• Earlobes increases ¼ longer ( cartilage)
  fatter

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Taste
9,000 taste buds 40 to 50 in women 50 to 60
in men After 60 loss of sensitivity sweet
salty 1st to go
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Smell

• smell receptors decreases increases the threshold
  for smell
• after 50 the sense of smell decreases rapidly
• 80 reduced by about half
• Size increases ½ in wider ½ in longer (
  cartilage)

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Interior

• Skeletal System
• Heart
• Brain
• Reproductive System

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Skeletal System

• bone density is lost (women after menopause)
• trunk becomes shorter (disks lose fluid
• - thinner)
• vertebrae lose some of minerals
• (bone also becomes thinner)
• spinal column becomes curved and compressed
• long bones (arms legs) brittle (mineral loss)
• no change length ? arms and legs look longer
• when compared to shortened trunk.

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Osteoporosis resorption of bone by clasts
thin, fragile, brittle
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Heart

• Generally, maintains size
• Except left ventricle
• walls thicken (enlarges)
• Isolated systolic hypertension
• Arteries
• loss elasticity hardening of
• the arteries (arteriosclerosis)
• narrowing of passage in artery due to plaque
  (atherosclerosis)

120 systolic ? contract pushing blood out
----- 80 diastolic ? ventricles refill with
blood
BP
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Leading cause of death
1.
2.
6.
3.
4. COPD 5. Pneumonia
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Brain
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2 mo
This example shows progressive loss of the
dendritic surface in aged human dentate gyrus
granule cells OR NOT
24 mo
24 mo old rat
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Max weight at 20 (3 lbs) loss of 10 over
lifetime
No widespread loss of neurons! Maintains
most Neurons Frontal, Parietal Striate Loss
in nucleus Basalis Acetylchoiline memory
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Basal Ganglia

• Hub of motor activity
• responsible for initiating
• and integrating movements
• become bright with age due
• to iron accumulation
• No health problems are
• associated with this change

MRI of healthy 87 year old brain, next to a
healthy 27 (MRIs courtesy of the Oregon Brain
Aging Study.)
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Subarachnoid
As the brain becomes smaller as a result of the
gradual, life-long loss of brain cells, this
area increases in size to fill the space
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Hippocampus
Memory center of the brain There is some cell
loss associated with healthy aging, but this by
itself does not indicate significant memory loss
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Ventricles
Hollow spaces filled with CSF Like the
subarachnoid space, these spaces increase in
size as the brain becomes smaller with age
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White Matter
Myelination communication channel for the
brain's information processing gray matter White
matter changes in appearance with aging. The
reason for these changes is unclear, but it may
be related to the normal slowing of information
processing in the brain with age
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• white matter decrease
• increase in ventricles
• increases in CSF
• Gray matter okay!

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Aging brain ? plasticity Dendrites!!

• Dopamine
• Acetylcholine
• D2 receptors
• DA slows metabolism

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Reproductive system - Female

• Females
• Menopause end of fertility
• loss of estrogen
• progesterone
• fat deposits in breasts
• loss of skin elasticity
• facial hairs
• 50 45-50
• 25 before 45, 25 after
• 2 to 3 years to complete

No ovum Decrease in size uterus, cervix, vagina
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Reproductive system - Male

• Andropause
• testicular tissue mass decreases
• testosterone same decreases slightly
• sperm still produced
• erectile function impaired
• No abrupt change
• Fertility issues (94 yr old)
• Prostate enlarges (50)

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• Men
• longer to achieve full erection
• takes longer to orgasms
• fewer genital spasms
• longer to 2nd erection

• Women
• longer time to respond to
• sexual stimuli
• orgasms less intense shorter
• duration

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Survey of over 10,000 people (42 responding)